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"Schneider, Christin"
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Metabolism of remimazolam in primary human hepatocytes during continuous long-term infusion in a 3-D bioreactor system
2019
Remimazolam is an ultra-short acting benzodiazepine under development for procedural sedation and general anesthesia. It is hydrolyzed by CES1 to an inactive metabolite (CNS7054).
In this study, the effect of continuous remimazolam exposure on its metabolism and on
expression was investigated in a dynamic 3-D bioreactor culture model inoculated with primary human hepatocytes.
Remimazolam was continuously infused into bioreactors for 5 days at a final concentration of 3,000 ng/ml (6.8 µM). In parallel, 2-D cultures were run with cells from the same donors, but with discontinuous exposure to remimazolam.
Daily measurement of clinical chemistry parameters (glucose, lactate, urea, ammonia, and liver enzymes) in culture supernatants indicated no noxious effect of remimazolam on hepatocyte integrity as compared to untreated controls. Concentrations of remimazolam reached steady-state values of around 250 ng/ml within 8 hours in 3-D bioreactors whereas in 2-D cultures remimazolam concentrations declined to almost zero within the same time frame. Levels of CNS7054 showed an inverse time-course reaching average values of 1,350 ng/ml in perfused 3-D bioreactors resp. 2,800 ng/ml in static 2-D cultures. Analysis of mRNA expression levels of
indicated no changes in gene expression over the culture period.
The results indicated a stable metabolism of remimazolam during 5 days of continuous exposure to clinically relevant concentrations of the drug. Moreover, there was no evidence for a harmful effect of remimazolam exposure on the integrity and metabolic activity of in vitro cultivated primary human hepatocytes.
Journal Article
Cold atmospheric plasma causes a calcium influx in melanoma cells triggering CAP-induced senescence
by
Bosserhoff, Anja-Katrin
,
Gebhardt, Lisa
,
Karrer, Sigrid
in
631/67/1059
,
631/67/1813/1634
,
631/80/86
2018
Cold atmospheric plasma (CAP) is a promising approach in anti-cancer therapy, eliminating cancer cells with high selectivity. However, the molecular mechanisms of CAP action are poorly understood. In this study, we investigated CAP effects on calcium homeostasis in melanoma cells. We observed increased cytoplasmic calcium after CAP treatment, which also occurred in the absence of extracellular calcium, indicating the majority of the calcium increase originates from intracellular stores. Application of previously CAP-exposed extracellular solutions also induced cytoplasmic calcium elevations. A substantial fraction of this effect remained when the application was delayed for one hour, indicating the chemical stability of the activating agent(s). Addition of ryanodine and cyclosporin A indicate the involvement of the endoplasmatic reticulum and the mitochondria. Inhibition of the cytoplasmic calcium elevation by the intracellular chelator BAPTA blocked CAP-induced senescence. This finding helps to understand the molecular influence and the mode of action of CAP on tumor cells.
Journal Article
Acidified Nitrite Contributes to the Antitumor Effect of Cold Atmospheric Plasma on Melanoma Cells
by
Bosserhoff, Anja-Katrin
,
Zimmermann, Tom
,
Karrer, Sigrid
in
Acidification
,
Antineoplastic Agents - pharmacology
,
Apoptosis
2021
Cold atmospheric plasma (CAP) is partially ionized gas near room temperature with previously reported antitumor effects. Despite extensive research and growing interest in this technology, active components and molecular mechanisms of CAP are not fully understood to date. We used Raman spectroscopy and colorimetric assays to determine elevated nitrite and nitrate levels after treatment with a MiniFlatPlaster CAP device. Previously, we demonstrated CAP-induced acidification. Cellular effects of nitrite and strong extracellular acidification were assessed using live-cell imaging of intracellular Ca2+ levels, cell viability analysis as well as quantification of p21 and DNA damage. We further characterized these observations by analyzing established molecular effects of CAP treatment. A synergistic effect of nitrite and acidification was found, leading to strong cytotoxicity in melanoma cells. Interestingly, protein nitration and membrane damage were absent after treatment with acidified nitrite, thereby challenging their contribution to CAP-induced cytotoxicity. Further, phosphorylation of ERK1/2 was increased after treatment with both acidified nitrite and indirect CAP. This study characterizes the impact of acidified nitrite on melanoma cells and supports the importance of RNS during CAP treatment. Further, it defines and evaluates important molecular mechanisms that are involved in the cancer cell response to CAP.
Journal Article
Bile canaliculi formation and biliary transport in 3D sandwich-cultured hepatocytes in dependence of the extracellular matrix composition
2016
Primary human hepatocytes (PHH) are still considered as gold standard for investigation of in vitro metabolism and hepatotoxicity in pharmaceutical research. It has been shown that the three-dimensional (3D) cultivation of PHH in a sandwich configuration between two layers of extracellular matrix (ECM) enables the hepatocytes to adhere three dimensionally leading to formation of in vivo like cell–cell contacts and cell–matrix interactions. The aim of the present study was to investigate the influence of different ECM compositions on morphology, cellular arrangement and bile canaliculi formation as well as bile excretion processes in PHH sandwich cultures systematically. Freshly isolated PHH were cultured for 6 days between two ECM layers made of collagen and/or Matrigel in four different combinations. The cultures were investigated by phase contrast microscopy and immunofluorescence analysis with respect to cell–cell connections, repolarization as well as bile canaliculi formation. The influence of the ECM composition on cell activity and viability was measured using the XTT assay and a fluorescent dead or alive assay. Finally, the bile canalicular transport was analyzed by live cell imaging to monitor the secretion and accumulation of the fluorescent substance CDF in bile canaliculi. Using collagen and Matrigel in different compositions in sandwich cultures of hepatocytes, we observed differences in morphology, cellular arrangement and cell activity of PHH in dependence of the ECM composition. Sandwich-cultured hepatocytes with an underlay of collagen seem to represent the best in vivo tissue architecture in terms of formation of trabecular cell arrangement. Cultures overlaid with collagen were characterized by the formation of abundant bile canaliculi, while the bile canaliculi network in hepatocytes cultured on a layer of Matrigel and overlaid with collagen showed the most branched and stable canalicular network. All cultures showed a time-dependent leakage of CDF from the bile canaliculi into the culture supernatant with variations in dependence on the used matrix combination. In conclusion, the results of this study show that the choice of ECM has an impact on the morphology, cell assembly and bile canaliculi formation in PHH sandwich cultures. The morphology and the multicellular arrangement were essentially influenced by the underlaying matrix, while bile excretion and leakage of sandwich-cultured hepatocytes were mainly influenced by the overlay matrix. Leaking and damaged bile canaliculi could be a limitation of the investigated sandwich culture models in long-term excretion studies.
Journal Article
Smart exercise in pediatric oncology: enhancing executive functions through cognitively challenging physical activity– a non-randomized controlled trial
by
Furtwängler, Rhoikos
,
Schneider, Ann Christin
,
von der Weid, Nicolas
in
Adolescent
,
Biomedical and Life Sciences
,
Biomedicine
2025
Introduction
Children and adolescents, diagnosed with cancer, frequently develop physical and cognitive impairments. Hence, cancer and its treatments contribute to reduced physical activity (PA) and cognitive impairments, particularly in executive functions (EFs). Research indicates that PA in school children improves EFs, with cognitively challenging PA offering potential additional benefits. The aim of this study is to investigate the effects of cognitively challenging PA during acute cancer care on cognitive and physical performance, as well as mental health.
Methods
This prospective, two-arm, non-randomized, multicenter controlled study will take place at four pediatric oncology centers in Switzerland. In the intervention group the effect of cognitively challenging PA (
n
= 35) will be compared with standard care plus PA recommendations in the control group (
n
= 35) in newly diagnosed pediatric patients with cancer aged 6-17.99 years. The twelve-week cognitively challenging PA intervention consists of three-weekly 45-minute individualized and supervised sessions incorporating cognitive elements. Assessments of EFs, motor abilities, cardiovascular health, health-related quality of life, fatigue, and physical and psychosocial functioning will be conducted at baseline, six weeks, twelve weeks, and a six month follow-up. All participants in the intervention and control group will receive PA recommendations during the intervention period and an offer for post-therapy PA counseling.
Discussion
Childhood is a crucial period for brain and motor development, rendering young cancer patients especially vulnerable to cognitive and physical impairments from the disease and its treatment. This study is the first to implement cognitively challenging PA tailored to pediatric cancer patients with the aim to enhance EFs by activating brain networks responsible for higher-order processes, physical performance and mental health. The findings will provide insights into the role of cognitively challenging PA and explore its integration into standard care to improve quality of life for childhood cancer survivors.
Trial registration
ClinicalTrials.gov (NCT06839794) and German Clinical Trial Register (DRKS00036573)
Journal Article
Acidification is an Essential Process of Cold Atmospheric Plasma and Promotes the Anti-Cancer Effect on Malignant Melanoma Cells
by
Bosserhoff, Anja-Katrin
,
Gebhardt, Lisa
,
Karrer, Sigrid
in
Acidification
,
Apoptosis
,
Calcium (intracellular)
2019
(1) Background: Cold atmospheric plasma (CAP) is ionized gas near room temperature. The anti-cancer effects of CAP were confirmed for several cancer types and were attributed to CAP-induced reactive species. However, the mode of action of CAP is still not well understood. (2) Methods: Changes in cytoplasmic Ca2+ level after CAP treatment of malignant melanoma cells were analyzed via the intracellular Ca2+ indicator fura-2 AM. CAP-produced reactive species were determined by fluorescence spectroscopic and protein nitration by Western Blot analysis. (3) Results: CAP caused a strong acidification of water and solutions that were buffered with the so-called Good buffers, while phosphate-buffered solutions with higher buffer capacity showed minor pH reductions. The CAP-induced Ca2+ influx in melanoma cells was stronger in acidic pH than in physiological conditions. NO formation that is induced by CAP was dose- and pH-dependent and CAP-treated solutions only caused protein nitration in cells under acidic conditions. (4) Conclusions: We describe the impact of CAP-induced acidification on the anti-cancer effects of CAP. A synergistic effect of CAP-induced ROS, RNS, and acidic conditions affected the intracellular Ca2+ level of melanoma cells. As the microenvironment of tumors is often acidic, further acidification might be one reason for the specific anti-cancer effects of CAP.
Journal Article
Amorphous Doped Indium Tin Oxide Thin‐Films by Atomic Layer Deposition.Insights into Their Structural, Electronic and Device Reliability
by
Dippel, Ann‐Christin
,
Schneider, Jörg J.
,
Büschges, M. Isabelle
in
Adsorbed water
,
Advanced materials
,
atomic layer deposition
2025
Thin semiconducting films of magnesium doped indium‐ and tin oxide are prepared by thermal atomic layer deposition (ALD). The metal oxide films are deposited at 200 °C from the precursors trimethylindium, tetrakis(dimethylamido)tin, bis(ethylcyclopentadienyl)magnesium and water as oxidant. These thin‐films are observed to be amorphous by electron microscopy and X‐ray diffraction. However, they exhibited a near‐range atomic order with correlation lengths of up to 10 Å, as demonstrated by high energy total scattering at grazing incidence employing synchrotron radiation. Even minor alterations in composition reveal a significant impact on the thin‐film transistor (TFT) device parameters, due to magnesium's high oxygen binding capability and its ability to inhibit the formation of oxygen vacancies, resulting in a decrease of free charge carriers in the material. Stability tests indicate a device degradation after storage in ambient conditions due to water adsorption on the surface, which could be reversed by an additional annealing step which qualify the films as robust. This studie demonstrate the possibility of employing minor amounts of high band gap oxides such as MgO to manipulate and control the electric behavior of the active channel layer performance in inorganic TFT devices. Controlled doping of magnesium oxide into indium/tin oxide binary thin‐films allows to manage their thin‐film transistor (TFT) parameters. Variation of mobility (µsat), threshold‐voltage (Vth), and on/off ratio (IOn/IOff) allows insight into the variation of the electron conduction mechanism in these semiconductor films. Despite the amorphicity of the films, structural information on the Angstroem level is provided by employing high energy total scattering under 0.02° gracing incidence.
Journal Article
Shared pathway-specific network mechanisms of dopamine and deep brain stimulation for the treatment of Parkinson’s disease
by
Faust, Katharina
,
Schneider, Gerd-Helge
,
Köhler, Richard M.
in
59/36
,
59/57
,
631/378/1689/1718
2025
Deep brain stimulation is a brain circuit intervention that can modulate distinct neural pathways for the alleviation of neurological symptoms in patients with brain disorders. In Parkinson’s disease, subthalamic deep brain stimulation clinically mimics the effect of dopaminergic drug treatment, but the shared pathway mechanisms on cortex – basal ganglia networks are unknown. To address this critical knowledge gap, we combined fully invasive neural multisite recordings in patients undergoing deep brain stimulation surgery with normative MRI-based whole-brain connectomics. Our findings demonstrate that dopamine and stimulation exert distinct mesoscale effects through modulation of local neural population activity. In contrast, at the macroscale, stimulation mimics dopamine in its suppression of excessive interregional network synchrony associated with indirect and hyperdirect cortex – basal ganglia pathways. Our results provide a better understanding of the circuit mechanisms of dopamine and deep brain stimulation, laying the foundation for advanced closed-loop neurostimulation therapies.
Dopaminergic medication and deep brain stimulation exert a shared therapeutic modulation of cortex-subthalamic nucleus network activity in Parkinson’s disease, through a suppression of high beta synchrony mediated by the hyperdirect pathway.
Journal Article
“Feel the need to prepare for Armageddon even though I do not believe it will happen”: Women Veterans’ Firearm Beliefs and Behaviors during the COVID-19 Pandemic, Associations with Military Sexual Assault and Posttraumatic Stress Disorder Symptoms
2023
Firearm purchasing increased within the U.S. during the coronavirus disease 2019 pandemic. While rates of firearm ownership and suicide are elevated among women Veterans compared to women non-Veterans, no studies have examined if and how firearm beliefs and behaviors changed among women Veterans during the pandemic. We examined women Veterans' changes in firearm beliefs and engagement in firearm behaviors during the early pandemic era.
3,000 post-9/11 era women Veterans were invited to participate in a survey. 501 respondents (May-December 2020) comprised the sample for this concurrent nested mixed-method analysis. Thematic analysis and log-binomial regression were used.
13.88% (n = 69) of women Veterans in our sample reported changes in their firearm beliefs; 22.15% (n = 109) reported engaging in firearm behaviors. The most prevalent reported behaviors were making household firearms more accessible (16.13%) and purchasing ammunition (11.97%). Smaller percentages reported carrying a firearm more frequently (6.71%), loading previously unloaded firearms (5.69%), or purchasing a firearm (4.24%). Thematic analysis suggested firearm behaviors were likely driven by a perceived increased need to protect oneself, family, and property due to: (1) uncertainties brought on by the pandemic; (2) pandemic-related threats necessitating self-defense, preparedness, and self-sufficiency; (3) political, social, and racial unrest and protests. PTSD symptom severity and military sexual assault history were associated with higher prevalence of changes in firearm beliefs and engagement in firearm behaviors during the pandemic.
Consideration of women Veterans' prior experiences and pandemic-related factors may be necessary to contextualize firearm discussions and inform future research. Given associations of military sexual assault and PTSD symptoms with firearm beliefs and behaviors, it may be crucial to ensure that such discussion are trauma-informed.
Journal Article
Neurodevelopmental toxicity assessment of flame retardants using a human DNT in vitro testing battery
2022
Due to their neurodevelopmental toxicity, flame retardants (FRs) like polybrominated diphenyl ethers are banned from the market and replaced by alternative FRs, like organophosphorus FRs, that have mostly unknown toxicological profiles. To study their neurodevelopmental toxicity, we evaluated the hazard of several FRs including phased-out polybrominated FRs and organophosphorus FRs: 2,2′,4,4′-tetrabromodiphenylether (BDE-47), 2,2′,4,4′,5-pentabromodiphenylether (BDE-99), tetrabromobisphenol A, triphenyl phosphate, tris(2-butoxyethyl) phosphate and its metabolite bis-(2-butoxyethyl) phosphate, isodecyl diphenyl phosphate, triphenyl isopropylated phosphate, tricresyl phosphate, tris(1,3-dichloro-2-propyl) phosphate, tert-butylphenyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, tris(1-chloroisopropyl) phosphate, and tris(2-chloroethyl) phosphate. Therefore, we used a human cell–based developmental neurotoxicity (DNT) in vitro battery covering a large variety of neurodevelopmental endpoints. Potency according to the respective most sensitive benchmark concentration (BMC) across the battery ranked from <1 μM (5 FRs), 1<10 μM (7 FRs) to the >10 μM range (3 FRs). Evaluation of the data with the ToxPi tool revealed a distinct ranking (a) than with the BMC and (b) compared to the ToxCast data, suggesting that DNT hazard of these FRs is not well predicted by ToxCast assays. Extrapolating the DNT in vitro battery BMCs to human FR exposure via breast milk suggests low risk for individual compounds. However, it raises a potential concern for real-life mixture exposure, especially when different compounds converge through diverse modes-of-action on common endpoints, like oligodendrocyte differentiation in this study. This case study using FRs suggests that human cell–based DNT in vitro battery is a promising approach for neurodevelopmental hazard assessment and compound prioritization in risk assessment.
Journal Article